A progressive die is one of the most common of dies, and, in use, one of the fastest, for making sheet metal stamped parts. Finished edges of the parts are tied together by a portion of the original strip or coil called a carrier, bridge, ribbon, etc. which becomes “off-fall,” i.e., waste. See, e.g., U.S. Pat. No. 7,249,546 B1 to Fosnaugh.
A carrierless progressive die is a progressive die without a carrier between parts to tie the parts together. Instead, parts are connected finished edge to finished edge, eliminating off-fall. See, e.g., U.S. Pat. No. 6,408,670 B1 to Trapp.
Transfer dies are special line dies that are timed together and properly spaced an even distance apart in press(es). Sheet metal stamped parts are transferred by special traveling rails mounted within the press boundaries, and there is no carrier between parts. These rails most commonly are mounted on each side of the dies. During the press cycle, each rail travels inward, grabs the part with special fingers, and then transfers it to the next die. See, e.g., U.S. Pat. No. 4,513,602 to Sofy.
Some typical advantages and disadvantages of each type of die are listed below.
Progressive die advantages typically include:
                A great volume of parts can be produced very quickly.        It can be run unattended.        Only one press is required.        The press is smaller than a transfer press.        It is usually less costly to produce than larger, more complex transfer dies.Progressive die disadvantages typically include:        Due to the carrier, more material is used than in carrierless progressive or transfer dies.        Parts cannot be turned over or rotated during the stamping process.        Access to the part profile is limited due to the carrier.        Progression, i.e., distance between parts, on the stamping line is fixed.Carrierless progressive die advantages typically include:        A great volume of parts can be produced very quickly.        It can be run unattended.        Only one press is required.        The press is smaller than a transfer press.        It is usually less costly to produce than larger, more complex transfer dies.        No carrier between parts is present, which allows for material savings.Carrierless progressive die disadvantages typically include:        Parts cannot be turned over or rotated during the stamping process.        Access to the part profile is limited by the finished edge to finished edge contact.        Progression on the stamping line is fixed.Transfer die system advantages typically include:        Large parts can be handled at fairly rapid speeds.        Parts can be turned over or rotated during the stamping process.        Parts have no carrier, allowing for material savings.        Access to the entire part profile is available.        Progression on the stamping line can be varied.Transfer die system disadvantages typically include:        More than one press may be required, usually quite large.        Often a high cost is entailed to make or purchase the movement device of the system.        A somewhat unpredictable installation cost can be entailed.        Systems are is usually specific to and made for certain applications only, i.e., They are usually “custom” or “customized” items, not “off the shelf” items.        Sophisticated electronics and mechanical finger motion are often required to function properly.        More die protection sensors are required than for progressive and carrierless progressive dies.        Pitch, i.e., re-created progression typically on a horizontal plane, motion is mechanically separated from drive motion, i.e., motion typically orthogonal to pitch on the horizontal plane, adding complexity and synchronization problems.        
It is also known in a progressive die to remove the carrier and perform work on the separated part. One simple example of this may be considered to be where, in a progressive die, the carrier feature is cut off at the last station to leave the part, and a simple mechanical device is used to move the separated part away from the line, perhaps to work on it. Some typical advantages of such a system typically include advantages similar to those attending progressive or carrierless progressive dies such as listed above; the system can be bought off the shelf; and relative simplicity is maintained. Some typical disadvantages of such a system typically include disadvantages similar to those attending progressive or carrierless progressive dies such listed above; more varied work is limited until the end of the line; only one station is available for such additional varied work; limited motion is provided; and essentially this amounts to a mere ejection device. At the other extreme, the carrier feature may be removed after the first station on a progressive line, and a sophisticated device is used to move the separated part to successive transfer stations to work on it, thus providing progressive and transfer capabilities. See, e.g., U.S. Pat. No. Re. 34,581 (from U.S. Pat. No. 4,833,908) to Sofy et al. Some typical advantages of such a system typically include advantages attending transfer die systems such as listed above; and pre-work can be carried out on the part such as oiling, cleaning, pre-forming, for which progressive or carrierless progressive dies are noted. Some typical disadvantages of such a system typically include disadvantages similar to those attending transfer die systems such as listed above; the system remains expensive, big, and complex; access to tooling can be severely limited because it is buried within the transfer system structure, therefore, with maintenance and re-tooling difficult; and the pitch motion providing device in the transfer stations is still mechanically separate from drive, with complexity and synchronization problems remaining.
Additional art is known. See, U.S. Pat. Nos. 3,165,192 to Wallis; 3,707,908 to Merk et al.; 3,754,667 to Storch; 3,756,425 to Wallis; 3,939,992 to Mikulec; 4,311,429 to Wallis; 4,540,087 to Mizumato; and 4,895,013 to Sofy. See also, U.S. Pat. Nos. 3,939,992 to Mikulec; 4,735,303 to Wallis; and 4,852,381 to Sofy; plus U.S. Pat. No. 6,327,888 B1 to Kadlec. Note, U.S. Pat. No. 4,331,315 to Geisow.
It would be desirable to improve upon or supply an alternative to the art.